Interview question about RF field test and RF power sources

asked in a interview and I have no idea what the interviewer is asking and how to answer.

Here is the question: When you do a RF filed test, there are several RF power sources, either come from a facility or from car or whatever, when conserdering the correlation of these different sourses. What's you first step to do or what your consern is about?

Thanks

in a an RF field test you will have your own Tx and Rx. So the other transmitters around are interferers. It is very important to do proper filtering in our Rx. moreover the IP3 point of our receiver is very important. consider a strong out-band interference that has been rejected by 40dB but still enough strong that some imags (say 2f0-f) is in the band.
both of these two interferences (linear and non-linear) may suffer the measurement